The sdump() function might trigger a heap-based buffer overflow
during the escaping of non-printable characters with the high bit set
from an X.509 certificate (CVE-2010-0562).

The vendor reported
that Fetchmail does not properly handle Common Name (CN) fields in
X.509 certificates that contain an ASCII NUL character. Specifically,
the processing of such fields is stopped at the first occurrence of a
NUL character. This type of vulnerability was recently discovered by
Dan Kaminsky and Moxie Marlinspike (CVE-2009-2666).

Impact

A remote attacker could entice a user to connect with Fetchmail to a
specially crafted SSL-enabled server in verbose mode, possibly
resulting in the execution of arbitrary code with the privileges of the
user running the application. NOTE: The issue is only existent on
platforms on which char is signed.

Furthermore, a remote attacker might employ a specially crafted X.509
certificate, containing a NUL character in the Common Name field to
conduct man-in-the-middle attacks on SSL connections made using
Fetchmail.